
public class RomanToInt {
      public static int roInt(String s) {
    	  if (s == null) return 0;
    	  int d = s.length();
    	  char c = s.charAt(--d);
    	  int l = convert(c);
    	  int result = l;
    	  for(int i = s.length() - 2; i >= 0; i--){
    		  char cc = s.charAt(i);
    		  int ll = convert(cc);
    		 
    		  if(ll >= l)
    			  result += ll;
    		  else if(ll < l)
    			  result -= ll;
    		  l = ll;
    	  }
    	  return result;
      }
      public static int convert(char c) {
    	  switch (c) {
    		  case 'I' : return 1;
    		  case 'V' : return 5;
    		  case 'X' : return 10;
    		  case 'L' : return 50;
    		  case 'C' : return 100;
    		  case 'D' : return 500;
    		  case 'M' : return 1000;
    		  default : return 0;
    	  }
      }
      public static void main(String[] args){
    	  System.out.println(roInt("III"));
    	  System.out.println(roInt("VIII"));
    	  System.out.println(roInt("IV"));
    	  System.out.println(roInt("DCI"));
    	  System.out.println(roInt("MCMXCVI"));
      }
}


